Yeast hydrolysate supplement increases starvation vulnerability of Queensland fruit fly

Post-teneral diets containing yeast hydrolysate are reported to increase longevity, reproductive development and sexual performance of Queensland fruit fly (Q-fly') Bactrocera tryoniFroggatt (Diptera: Tephritidae). Consequently, diets including yeast hydrolysate are recommended for sterile Q-flies before release in sterile insect technique (SIT) programmes. However, in some tephritids, diets including yeast hydrolysate are associated with an increased vulnerability to starvation. In the present study, the effects of yeast hydrolysate supplementation before release are considered with respect to the longevity of released Q-fly when food becomes scarce. Experiments are carried out in three settings of varying resemblance to field conditions: 5-L laboratory cages, 107-L outdoor cages and 14140-L field cages containing potted citrus trees. In all experimental settings, compared with flies that received only sucrose, male and female Q-flies that are provided with yeast hydrolysate during the first 2days of adult life have a significantly shorter survival when subsequently deprived of food. Yeast supplementation appears to commit Q-flies to a developmental trajectory that renders them more vulnerable to starvation. The practical significance of these findings for SIT depends on how often the releases are carried out under conditions in which Q-flies experience extreme food shortages in the field.